Ideas anyone...4.5 Mystery overheating - NOT the usual suspects

[threedogs]

Never heard the term "tropical" is that just the heat range for your area? certainly got a unique problem but sure you'll get it sorted

[nissannewby]

Was each individual system pressure tested or just the the pressure tester in place of radiator cap? And has it only just started since its the weather has gotten colder?

[Thirsty]

X2 on the radiator cap

[zerolux]

pressure test was only in place of the radiator cap, CO tested the radiator as compression should blow into the water when running and water into cylinder when not.....New cap was fitted...took the oil cooler off today and took out some sludge buildup..So flushed the engine just to be sure..

was a fairly warm day the first time it happened and pretty cool the other day...

new viscous hub arrives monday, but have driven around yesterday and today and couldnt get it hot

checked the ECU today and got all clear on the Consult..so

I'll Just keep plugin away till I find somethin

[nissannewby]

It might be worth your while to test each system. The engine, heater and radiator if you can test all these individually and leave the pressure in the system for a prolonged period possibly even over night you could have the tiniest of cracks somewhere that hasnt shown up in previous test and could be why its intermittent.

[zerolux]

So, just an update...Thanks again for all your help, have tried everything, and just to show how intermittent this is, went to go on holidays yesterday and got 30 minutes out of town and it overheated...no lost water, no water in the oil, drove back from where it got hot to home and as long as i didnt go over 60 the temp stayed normal (although i did have the heater on full to try and draw some heat away which made the 32c day much nicer ) Did have the van on, so it had a fair load, but have had the van on a few times since the last overheating, so a couple of good months.

SO...Its off to nissan it goes, see if they can find an issue

Thanx again y'all
Jarrod

[threedogs]

I'd have a very good read of Goats thread on '10 model overheating.
everyone swore black and blue the radiator was ok/checked/pressure tested
by NISSAN. it still overheated, his mate rodded the radiator only half if that had water
flowing through it. Is your radiator BRAND NEW ?? or just been checked ??

What puzzles me is you don't need a fan at 100kph ,gotta be something simple
what happens over 60 that makes it boil, start the 4x4 up with cap off, let it get
warm and check for bubbles in the water

[zerolux]

Radiator is brand new, as are hoses, thermostat, coolant and temp sensors, water pump, clutch fan, have basically replaced the entire cooling system and related sensors, flushed, pressure tested, radiator has been CO tested for exhaust, engine has been compression tested, desludged and oil changed, it doesnt use water, no water in the oil, no water in the auto, power does seem a little down, but always kicks over first start and doesnt miss or knock...has me stumped and the fact that once you stop the car when its overheated and it cools down, then it might happen straight away or it may not happen for months, like when it overheated 120kms away from home, and when it cooled down, it drove back without getting past its running temp...FRUSTRATING

No bubbles in Radiator, but at this point a cracked head would be nice, at least i'd know what needed fixing

[threedogs]

Does it have a MAF sensor, still think we have all missed something

[nipagu7]

Hi Zerolux , just read thru the thread and saw that Threedogs earlier mentioned about earth connections , but i couldnot tell from your answers if you checked them or not. This would include commputer earths , battery to engine , battery to body , map sensor connections and oxygen sensor connections , and any other earth connections that seem in any way related to the ignition or fuel system . By checking them I mean loosening , cleaning and reseating , It,s amazing how just the slightest bit of corrosian can cause problems as computerised cars age. A bad earth could cause the car to start to run lean or rich and either can cause over heating .